Radio frequency identification (RFID) is becoming increasingly popular and the number of applications is rapidly expanding due to decreases in chip prices. Conventional applications for RFID technology, such as shown in British published patent application 2310977 and U.S. Pat. Nos. 4,783,646, 5,566,441, 5,817,207, and 5,867,102 (the disclosures of all of which are hereby incorporated by reference herein) include cards, labels, clothing tags, and the like. For many uses, utilizing conventional techniques, the production of RFID elements is relatively cumbersome, slow, and expensive. Such drawbacks are particularly problematic when it is desired to produce relatively inexpensive RFID elements, such as labels, or other business forms, such as mailer type business forms, or relatively simple cards.
According to the present invention, methods, as well as products produced according to the methods, are provided which can result in enhanced simplicity and speed of the construction of RFID elements. For example according to one aspect of the present invention RFID elements are made from a paper web which comprises a base substrate, and by utilizing a carrier comprising a blend of thermoplastic resins and waxes which are solid at ambient temperature but become fluid at elevated temperature, and which contain conductive polymer, or metal flakes (such as copper, silver, nickel, or aluminum), or a blend thereof, therein, and the antenna may be printed at speeds in excess of about 500 feet per minute on a wide variety of substrates. Also, in the manufacture of conventional RFID elements there may be difficulties in accurately placing a chip in an area to create a necessary dielectric when the antenna is printed with conductive polymer anchor toner. Also the chips may be knocked off the substrate in subsequent handling, which could more easily occur if the element is a mailable element, such as a mailer type business form, label, or the like. Therefore according to another aspect of the invention the chip can be pushed through the substrate from the opposite side of the substrate that the antenna is printed on, and secured in place with adhesive, so that the substrate itself provides the dielectric and chip placement need not be as accurate as in conventional situations, and the chip is more likely to be held in place.
A wide variety of other advantages may be provided according to the invention, which allows the production of linerless labels, allows unique protective coatings or substrates to be applied, and generally results in the cost effective, simple, and efficient production of radio frequency identification elements of a wide variety of types, including linerless labels and other types of business forms.
According to one aspect of the present invention a method of producing an RFID element is provided comprising: (a) Unwinding a flexible substantially dielectric base substrate web from a roll, the base substrate having first and second faces. (b) Printing a radio frequency identification antenna with conductive ink or toner on the substrate first face. (c) Spot printing a non-conductive material over a portion of the antenna for cross-over. (d) Printing a conductive cross-over element on the non-conductive material to complete the radio frequency identification antenna. (e) Bringing a radio frequency identification chip into operative contact with the radio frequency identification antenna. And, (f) providing at least one protective substrate or coating on at least one of the radio frequency identification chip and antenna.
The radio frequency identification chip has contacts (which may be tapered to a point or edge), and (e) may be practiced by pushing the radio frequency identification chip into operative contact with the base substrate second face, and by pressing the chip contacts through the base substrate from the second face thereof, into contact with the radio frequency identification antenna, and securing the radio frequency identification chip in place. Also (e) may be further practiced by securing the radio frequency identification chip in place with adhesive acting between the chip and the base substrate second face.
Alternatively, (e) may be practiced by overprinting part of the antenna on the first face of the base substrate with a non-conductive material, and by pushing the contacts into contact with the antenna. For example (e) may be further practiced by spot coating the non-conductive material so that openings therein for receipt of the contacts of the chip are provided, and by pushing the chip contacts through those openings.
According to one aspect of the invention (f) may be practiced by applying a coating of heat expandable microspheres to at least one of the chip and antenna, and heating the spheres to expand them and provide a flexible protective coating. Alternatively (f) may be practiced (typically when using a paper web as the base substrate) by applying a protective substrate with adhesive over at least one of the chip and antenna so as to adhesively secure the protective substrate to at least one face of the base substrate. The method may further comprise (g) applying a pressure sensitive adhesive to the at least one protective substrate or coating, so that the element function as a label. For example (f) may be practiced by applying a protective substrate or coating to both faces of the base substrate; and (g) may be practiced to provide pressure sensitive adhesive to one of the protective substrates or coating, and a pressure sensitive adhesive release coating to the other of the protective substrates or coatings, so as to provide linerless labels. For example (a) through (g) may be practiced to produce a flexible web of RFID labels, and the method may further comprise taking up the web in roll form.
According to another aspect of the present invention a method of producing an RFID element using a substantially dielectric base substrate (such as paper) having first and second opposite faces and a RFID chip having contacts, is provided. The method comprises: (a) Printing a radio frequency identification antenna with conductive ink or toner on the substrate first face. (b) Bringing the radio frequency identification chip into operative contact with the radio frequency identification antenna by pushing the radio frequency identification chip into operative contact with the base substrate second face, and by pressing the chip contacts through the base substrate from the second face thereof, into contact with the radio frequency identification antenna, and securing the radio frequency identification chip in place. And, (c) providing at least one protective substrate or coating on at least one of the radio frequency identification chip and antenna. The details of the practice of (c), and the production of labels, the application particular protective substrates or coatings, or the like may be as described above.
The invention also relates to RFID elements produced from the methods as described above, and also relates to an RFID element which comprises: A substantially dielectric base substrate having first and second opposite faces. A radio frequency identification antenna of conductive material disposed on the first face of the base substrate. A radio frequency identification chip having contacts, the chip in operative association with the base substrate second face and the chip contacts penetrating the base substrate so that the contacts are in electrical contact with the antenna, and the base substrate substantially serves as a dielectric. And, at least one protective coating or substrate provided on at least one of the antenna and chip.
The element may further comprise a first protective coating or substrate covering the antenna and a second protective coating or substrate covering the chip. For example the element may further comprise a pressure sensitive adhesive provided on one of the first and second protective coatings or substrates, and a pressure sensitive adhesive release coat provided on the other of the first and second protective coatings or substrates, so that the element comprises a linerless label.
Alternatively the element may further comprise a pressure sensitive adhesive produced on the at least one protective coating or substrate, and a release liner provided over the pressure sensitive adhesive, so that the element comprises a linered label.
The antenna may comprise a Bistatil.RTM. antenna available from Motorola an antenna with cross-over. Preferably the element is flexible and is part of a roll of like, interconnected, flexible elements, and the base substrate is preferably paper, although other substrates may be utilized.
According to yet another aspect of the present invention there is provided a method of producing a radio frequency identification element from using a substantially dielectric base substrate having first and second opposite faces and a radio frequency identification chip having contacts, comprising: (a) Printing a radio frequency identification antenna with conductive ink or toner on the substrate first face. (b) Bringing the radio frequency identification chip contacts into operative contact with the radio frequency identification antenna. And, (c) providing at least one protective substrate or coating on at least one of the radio frequency identification chip and antenna by applying a coating of heat expandable microspheres to at least one of the chip and antenna, and heating the microspheres to expand them and flexible protective a flexible protective coating.
According to yet another aspect of the present invention there is provided a method of producing an RFID element comprising: (a) Printing a radio frequency identification antenna on the substrate first face using a printing media comprising a carrier including resin and wax which becomes fluid upon heating, and containing conductive materials therein, by heating the carrier so that it becomes fluid and is applied as a thick film on the substrate first face, and by allowing the carrier to cool so as to provide a conductive antenna. (b) After cooling of the carrier, bringing the radio frequency identification chip contacts into operative contact with the radio frequency identification antenna. And, (c) providing at least one protective substrate or coating on at least one of the radio frequency identification chip and antenna. The details of the printing of particular antennas (such as bistatik or cross-over antennas), or the production of labels, or other business forms or the like, may be as described above. Also in the practice of the invention (a) may be practiced (such as using paper as the base substrate) at a speed of about 500 feet per minute or more.
It is the primary object of the present invention to provide for the versatile, simple, yet effective production of RFID elements. This and other objects of the invention will become clear from an inspection of the detailed description of the invention and from the appended claims.